SUMMARY OF THE PRESENT INVENTION
In the manufacture of certain types of shoes a vamp panel is stitched to a top plug panel to form the major portion of the shoe upper. Typically the stitching operation is carried out along the toe and side edges of the plug panel. The present invention is concerned with a method of connecting the plug and vamp panels together so that the joint formed by the stitching is waterproof.
In a typical shoe construction the joint between the plug and vamp is not completely waterproof, since atmospheric water can seep through the interface formed by the stitching. Additional water can seep through the holes that hold the stitching thread.
The present invention contemplates a method of manufacturing shoes wherein the lower surface of the top plug and the mating surface of the vamp are pre-coated with a waterproofing material prior to the step of stitching the plug to the vamp. The stitching process pulls the coated surfaces together so that the merged coatings form an essentially continuous barrier to the seepage of water through the joint between the plug and vamp.
The action of the merged coatings is enhanced by placing the partially formed shoe in a drying oven. The waterproof coatings are typically formed of a tar-like material that tends to flow slightly when the partially-formed shoe is placed in a drying oven. The solvent carrier tends to vaporize, while the asphalt (tar) coating materials flow together, to eliminate any minute cracks or flow openings that might exist along the interface formed by the coatings.
To further enhance the waterproof action, an additional waterproof coating layer may be applied to the joint, on the interior surfaces of the plug and vamp panels. The additional waterproofing material provides insurance against water seepage through the joint between the plug and vamp.
Further features of the invention will be apparent from the attached drawings and description of a shoe construction formed by a manufacturing process that includes the method of the present invention.
In summary, and in accordance with the above discussion, the foregoing objectives are achieved in the following embodiments.
1. A method of forming a waterproof stitched connection between two shoe panels during a shoe manufacturing operation, comprising:
a) providing a coating of waterproofing material along one surface of a first panel that is to be stitched; PA1 b) providing a coating of waterproof material along one surface of a second panel that is to be stitched; PA1 c) bringing the coated surfaces of said panels together so that the two coating merge; PA1 d) stitching through coated areas of said panels so that each stitch extends through the coated interface between the panels; PA1 e) heating said panels to cause the interface coating to flow; and PA1 f) applying an additional coating of waterproofing material to the joint formed by the stitching, such that said additional coating merges with the previously applied coatings. PA1 g) forming a slit in said second panel after step (e) to gain access to the joint formed by the stitching. PA1 g) removing the partially-formed shoe from the shoe-forming last after step (e); and PA1 h) forming an access slit in said second panel after step (g) and before step (f). PA1 a) providing a coating of waterproofing material along the surface of the top plug panel that forms an inside surface of the finished shoe; PA1 b) providing a coating of waterproofing material along the surface of the vamp panel that ultimately forms an inside surface of the finished shoe; PA1 c) bringing the top plug panel and the vamp panel together on a shoe-forming last so that the coated surfaces form an interface between the two panels; PA1 d) stitching through the coated areas of said plug and vamp panels so that each stitch extends through the coated interface; PA1 e) placing the shoe-forming last in an oven to cause the waterproof coating materials to flow into intimate contact with the stitches; PA1 f) removing the shoe-forming last from the oven; PA1 g) removing the plug and vamp panels as a unit from the shoe-forming last; PA1 h) forming an access slit in said vamp panel; and PA1 i) applying an additional coating of waterproofing material to the joint formed by the stitching. PA1 j) reattaching the vamp panel areas that were previously severed by step (h); and PA1 k) applying a further coating of waterproofing material to the joint formed by step (j).
2. The method, as described in paragraph 1, wherein said one surface of each panel is an inside surface of the finished shoe.
3. The method, as described in paragraph 1, wherein said first panel is a top plug panel of the finished shoe, and said second panel is the vamp panel of the finished shoe.
4. The method, as described in paragraph 1, wherein step (d) is performed with said panels positioned on a shoe-forming last.
5. The method, as described in paragraph 4, wherein step (e) is performed by placing the shoe-forming last in a drying oven.
6. The method, as described in paragraph 5, wherein the partially-formed shoe is removed from the shoe-forming last between step (e) and step (f).
7. The method, as described in paragraph 5, wherein the partially-formed shoe is removed from the shoe-forming last after step (e); said method further comprising:
8. The method, as described in paragraph 5, and further comprising:
9. The method, as described in paragraph 1, wherein said first panel is a top plug panel of the finished shoe, and said second panel is the vamp panel of the finished shoe; said stitching step (d) being performed on the toe areas of said plug and vamp panels.
10. A method of forming a waterproof stitched connection between a top plug panel and a vamp panel during a shoe manufacturing operation, comprising:
11. The method, as described in paragraph 10, and further comprising: